I too am a Fixed blade user. I have used Thunderheads since the 80's! If I were to use mechanicals I would use the Spitfires myself. I have been looking at them hard but will still use my Thunderheads again this year. I have heard of great success using Spitfires. However, the fellows I know have switched to Grim Reapers and they say they leave blood trails a blind man can follow. I did a search on Grim Reapers here and on AT and it seems that most say they had problems with the Grim Reaper's blades not being sharp, bending on impact, and difficult to assemble.